[shangrila]

Aside from degradation, the difference the poster noticed in the display quality between the two different iPads can also be explained by two other phenomena:

- "Silent" hardware revs: Apple will frequently rev the hardware to fix issues without actually changing the model number (other than perhaps changing the range of numbers or adding a trailing suffix indicating the new revision). They certainly don't announce these announcing anything. The changes can include new parts, new firmware (which can be rolled out to existing hardware as an update if Apple considers it important enough), or fixed / updated boards. A newer iPad may have several improvements over an older one, even if it's ostensibly the same model.

- Multiple suppliers for the same production runs: even within the same revision, you can get two different instances of the same hardware with two different manufacturers for the same part. You could go to the store in a single trip and pick up two iPod Touches and end up with one that has a Sharp LCD and another one that has a Samsung LCD.